package com.utils;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5 算法
 * Created by Administrator on 2015/5/25.
 */
public class MD5 {
        // 全局数组
        private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",
                "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

        public MD5() {
        }

        // 返回形式为数字跟字符�?
        private static String byteToArrayString(byte bByte) {
            int iRet = bByte;
            // System.out.println("iRet="+iRet);
            if (iRet < 0) {
                iRet += 256;
            }
            int iD1 = iRet / 16;
            int iD2 = iRet % 16;
            return strDigits[iD1] + strDigits[iD2];
        }

        // 返回形式只为数字
        private static String byteToNum(byte bByte) {
            int iRet = bByte;
            System.out.println("iRet1=" + iRet);
            if (iRet < 0) {
                iRet += 256;
            }
            return String.valueOf(iRet);
        }

        // 转换字节数组�?6进制字串
        private static String byteToString(byte[] bByte) {
            StringBuffer sBuffer = new StringBuffer();
            for (int i = 0; i < bByte.length; i++) {
                sBuffer.append(byteToArrayString(bByte[i]));
            }
            return sBuffer.toString();
        }

        public static String GetMD5Code(String strObj) {
            String resultString = null;
            try {
                resultString = new String(strObj);
                MessageDigest md = MessageDigest.getInstance("MD5");
                // md.digest() 该函数返回�?为存放哈希�?结果的byte数组
                resultString = byteToString(md.digest(strObj.getBytes()));
            } catch (NoSuchAlgorithmException ex) {
                ex.printStackTrace();
            }
            return resultString;
        }
        
        /**
         * MD5运算
         *
         * @param s
         * @return
         */
        public static byte[] MD5Bytes(String s) {
            MessageDigest digest = null;
            try {
                digest = MessageDigest.getInstance("MD5");
                digest.update(s.getBytes());
                return digest.digest();
            } catch (NoSuchAlgorithmException e) {
                return null;
            }
        }
}
